Amazon Prime vs. Sam's Club vs. Costco: Which has the best deals?

Her smartphone has replaced her car when it comes to shopping for detergent and diapers.

"A quick two minutes, I’m set and it’s going to be in my mailbox or at my door the next day," she said.

Warehouse clubs fight back

Warehouse stores know you can get crock pots, clothing and paper towels easily online these days. So they are fighting back with products that are not so easy to get with a click of the mouse, such as discount tires, installed while you wait.

Don’t need tires?

Then what about prescription drugs? Or hearing aids? Or eyeglasses?

Consumer Reports Magazine says Sam’s Club and Costco's prices on those services are lower than most other chains. Their pharmacies have come in tops in several recent surveys by the magazine, with only online pharmacies offering lower prices.

But what if you just want household goods?

We turned to one of the top shopping bloggers in the country, the Krazy Coupon Lady, Joanie Demer.

Demer, her partner Heather Wheeler and her team recently compared prices on 170 popular items at Costco, Sam's and Amazon. They used Amazon's "Subscribe and Save" program, that gives an additional 5 percent discount on products you order every month.

So the survey's winners?

Costco came in first place, with the lowest prices overall.

"We found much to our surprise that Costco is still 12 percent less in the cost of the items than Amazon Subscribe and Save," Demer said.

Sam's Club was in second place, with prices 5 percent higher than Costco in their 170 item comparison.

But Demer warns that Costco’s relatively high $55 membership fee (compared with Sam's) means you need to shop more to see those savings.

"To make the Costco membership worthwhile you need to spend $600 or more per year to break even," she said.

Amazon Prime was the most expensive in her test (12 percent higher than Sam's and 7 percent higher than Costco) even with free shipping, and the extra discount offered by Subscribe and Save. Plus, it has a $99 annual fee, higher than either warehouse store.

However, with the extra discount provided by Amazon's "Subscribe and Save" program, Demer says diapers can actually be cheaper than the warehouse clubs. So she says new moms should consider it.

Price isn't everything

Demer says there's no single winner. Each store has its strengths, and one may be better for you, even if it costs a couple of dollars more.

She says:

Costco is best if you buy a lot, and don't mind the $55 membership fee and like to buy organic produce, which it has a great selection of on its shelves.

Sam’s Club is best for all those extra services, and membership fees as low as $5 to $10, if you grab one of their many promotions.

Amazon Prime is best for convenience. Plus with Amazon, you don't have the risk of buying stuff you don't need, simply because it is staring at you from an end cap or they have a free tasty sample in the store.

"The biggest danger with warehouse stores are impulse buys," Demer said, explaining that it is easy to spend another $20 per visit on stuff you never intended to buy.

Amazon Prime: Worth the convenience?

Ellen Glasgow knows she’s paying a bit more with Amazon Prime than with a warehouse membership, but is fine with that.

She said, "it’s worth the extra money. If you think about it, you’ve got to consider the gas, your car, your time. I can now budget a lot more time for my family and my husband."

So which of the two warehouse clubs is best? When it comes to Costco versus Sam's Club, where you live may make the decision for you.

If one warehouse club is 10 minutes away and the other is 45 minutes....the closer club will almost always make sense, even if it has higher membership fees or does not have all the items you want. That way you don't waste your money.

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“Don't Waste Your Money” is a registered trademark of Scripps Media, Inc. (“Scripps”). The information included in this article was obtained independently by Scripps reporters. While purchases from links inserted in this article may result in a commission for Scripps, no Scripps reporter benefited from that commission.

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